In at least one example application in the oil and gas industry, pumping units are used to draw crude oil from beneath the ground surface towards the surface for further transport via a pipeline to another location, such as an oil refinery. These pumping units are typically coupled to high pressure shutoff sensors, conventionally which are pressure switches often referred to in industry as Presco pressure switches or Presco for short. This type of shutoff sensor kills a motor of the pumping unit should the pressure on the pipeline exceed a prescribed threshold, thereby avoiding a failure on the pipeline such as a leak or rupture. Pumping units may also be found at spaced distances along the pipeline serving as booster stations for maintaining pressure along the pipeline. These may also be operatively coupled to Fresco's, so as to ensure longevity and safety with respect to the pipeline. More particularly, Oil-Well Pump-Jacks often are powered by single-cylinder engines, such as the Model C66 from Arrow Engines, most often fueled by propane or natural gas. They are typically wired as shown in FIG. 1 below, so as to be wired to shut-down in case the engine loses oil pressure, or the engine loses coolant, or if there is too much pressure in the pipeline that the pump-jack is pumping into.
If an engine does shut down, it is the responsibility of an oil-field operator to repair the problem and restart the engine. Usually the operator arrives on-site without any knowledge about what caused the shut-down. Traditionally, when troubleshooting a pumping unit so as to ascertain the cause for its shutdown, the Presco, which is connected by wires to the motor of the pumping unit, is disconnected from the motor so as to not prevent it from starting. By disconnecting the Presco, the motor is able to start in the event that the Presco is active and would otherwise continue to maintain the motor in a shut-down state. As such, a service technician may continue the diagnostic operation of the motor to determine if an issue localized to the motor of the pumping unit caused it to shutdown. During trouble-shooting of the problem, the operator thus unplugs the safety shut-downs to see which one caused the fault. For example, the motor may have shut down due to an ignition problem, overheating or insufficient oil pressure.
After the diagnostic operation has been completed, the service technician should reconnect the Presco to the motor so that this shutoff sensor remains operable to prevent failure of the pipeline should the pressure exceed a safe acceptable threshold. However, there remains the possibility that the technician forgets to do this, such that the Presco is not reconnected. If the operator forgets to re-connect the safety shut-down, and leaves the engine running, serious damage could occur to the engine or the pipe-line. A pipe-line rupture results in an oil spill, which is an environmental hazard and expensive to clean up.